Means for checking trackway devices



Nov. l0, 1931.

F. L, DODGSON FOR CHECKING TRACKWAY DEVICES l MEANS Filed April 2, 1925 2 Sheets-Sheet l Nov. 10, 1931. 1 r.| noDGsoN 1,831,232

MEANS FOR CHECKING TRACKWAY DEVICES Filed April 2, 1925 2 Sheets-Sheet 2 FIGB.

`10 device.

fu-Nirsn STA kERAIN'K L. DODGSON, OF -ROCHESTEI NEW aromi, .AssiGNon To GENERAL RAILWAY ,SIGNALV COMPANY, OIE ROCHESTER, NEW YORK MEA-Heros; ,Gaat-1eme TRAGKWAY DEVICES Application mea April 12,

` This invention relates to trackvvay apparatus for train control systems ,of the intermittent type, and moreparticularlyto means for preventing the Wayside signal ad]acent 5 the traclWay device Jfrom indicating clear or proceed Whenever such trackiv'ay device 1s kin fa. danger traffic lcondition even ,though it is in suchcondition by reason offailure of an essential part` or circuit ofsuchtrackway i Influence communicatingmeans for, transmitting.contr-ol influences from the trackvvay tothe moving train in train control systems of `the intermittent type and especially iif 15 such influence communicating means is used to transmit influences corresponding to adverse tratlicconditions ahead,are constructed toifunction on. the side of safety, that is, are constructed on the closed circuit prnciplqso 2 0 that, the failure of-a circuit or circuits there- `of causes an influence to be communicated. In systemsfof thiskind the failure offsuch circuit of the influencecommunicating means causes a control influence .to be; transmitted g5 even though the-Wayside signal indicates clear vand traic conditionsahead are favorable. It

Vis especiallybad to transmit a stopping-control .influence to a `,moving ltrain when the signal adjacent thereto .is in a. clear condi- .",o tion in systems of the .automatic lst-opt type I (systems Ain which the transmission of an .in-`

V:iuence effects a brake application) because a .sudden land unexpected V.brake application, which in itself isdangerous, takes Yplace upon vpassage of the train by a .defective traclwa'y device. 'This is-y also true .of permissive systems .orsystemsof .the speed controltype employing. acknowledging features, because in these'` latter systems a. c brake application 4o taires, place ..by reason ofthe kfailure .of the l engineento l manifest vigilance V'when f passingsuch a defective. trackway:deviceeven though theengineer Was, vigilantin looking outiorV waysidel signals iny a restrictive con- 45 [ditie @dressed `weide ssnaL Anfunex- 119275. serial No, 20,144.

pected b'rakejapplication in systems offthe latter type doesnot only necessarily restrict the speed oit the train Vbut may result in Wrecking'a train.

:in .accordance with the present'invention,

Vwhich has been shown applied only to ramp f` systems and systems einployingftrackway devices of the inert inductor type in which type a circuit of low resistance is closed under clear traiiic conditions ahead, it is proposed to cause thes'ignal `adjacent to which such trackvvay ldevice is placed to assume-the danger condition, or at least, again i-fail to assume the `clear condition `after once having assumed the danger condition, if the trackivay f device is condition byV reason oftheffact that it is constructed onthe closed circuit principle and is outo'f order. Another'object of the present invention resides in the-provision of Vmeans which causesa Waysidey signal-to assume its danger position-if the trackvvay in- :luence communicating'device adiacent thereto'is accidentally or maliciously taken away.V

V-Qther objects, purposes and speci'ic fealtures ofthe invention will in part be1 lpointed ont and Vin'part be obvious from the description hereinafter given.

VIn describing the invention in detail reference Willibe made to the accompanying draw- Fig. ll illustrates a control Apoint of the trac'kway apparatus of a train control sys- Yteniof the 'intermittent type inWhich the pick up circuit for a stick home relay -is comthereof i i-r in'its danger andriniiuence'communicating that s hOWnin Fig. `1eXcept that lthere'fis circuits in multiple each including a part of the low resistance coil, and in which a resistance is at times connected in series with this check relay and source of current; and

Fig. 4 shows an arrangement of the invention similar to that shown in Fig. 2 but applied to a ramp system. Y

Structure (F 71g. Z

sumes the deenergized and energized posi-V tion if the block is occupied and unoccupied respectively. The home relay H re ects traliic conditions of a portion of the trackway in advance thereof, and is controlled in the usual way. InV the particular arrangement shown the circuit of the home relay H includes in series therewith the front con- Y tacts of the track relays T and Tl of the two sections of the block J. Further, a distance relay D is provided which is controlled by the home relay H of the block in question and the home relay'of the block next in advance. The relay D in combination with the home relay H control a three-position semaphore signal Z of the usual construction, and for convenience this semaphore signalZ hasbeen shown conventionally without illustrating its control mechanism and by merely showing its clear and caution controlcircuits @Z and @a respectively leading into the signal.

Adjacent the signal Z and preferably a short distance in the rear thereof, the normal direction of traffic being as indicated by the arrow, is located an influence communicating device E, which in the specific arrangement shown is one of the inert inductor type and comprises a core 4: of laminated magnetic material terminating in upwardly facing pole pieces 5 and having a coil 6 on the back yoke thereof, which coil is closed in ay circuit of low resistance when this device is in its ineffective or non-influence communicating condition. y

Under normal clear traihcV conditionsof the particular apparatus shown, the home relay H is energized through a circuit beginning at the battery 8 located at the next signal Z1 in advance, wire 9a,contact 10a. of relay TRwire 9, front contact 10 of the track relay T, winding of the home relay H, wire 11, coil 6 of the track element E, wires 14 and 15 to a common return wire C connected yto the other terminal of said battery, so that this relay H can be picked up if the complete block J is unoccupied. Similarly, distant relay D is picked up by a pick-up circuit beginning at the battery 8 of the block in advance, through contact 20 of the relay H of the signal location in advance, the contact 21 operated by the signal blade of the signal at the signal location in advance and closed under both clear and caution conditions of such signal, wire 16 front contact 17 of the home relay H of the signal location in question, winding of the distant relay D of the signal location in question, wire 18, coil 6 of the track element E, wires 14 and 15 back to the common return wire C. It should be noted that the circuit for the relays H and D just traced are pick-up circuit-s, and that the stick circuits for these relays include the contact 12`of the relay D which relay D is controlled by relay H. vIn other words, the integrity of the coil Gis necessary to pick up relays H' and D, but such integrity is not necessary to'hcld the relaysH and D energized if they have oncev assumed their energized condition.

opa-am (Fig. 1) Y In order to understand how the embodiment ofthe invention illustrated in Fig. 1 causes the signal Z to assume the danger position if an open circuit develops in the low resistance coil of the track element E, let us assume that the apparatus shown in Fig. 1 is in its normal clear trafc conditionV as illust'rated and that there is a train moving from left to right from the block I into the block J. As soon as the train gets into the block J the track relay T is cle-energized thereby dropping the home relay H and in turn the distant relay'D. Dropping of the home relay H opens both the caution circuit 0a and the clear circuit el, this clear circuit cl also being opened by dropping of contact 19 of the distantrelay D, so that the signal Z assumes its danger indicating position. These circuits include the battery 8 and the front contact i 20 of the home relay H and are readily traced in the drawing. Dropping of the distant relay D opens the circuit for the low resistance coil 6 by dropping its contact 12, so that the trackway device E is now in its active stopping condition. Let us assume that due to'the vibration of this train, or the like, as it passes this control point, an open circuit develops inthe coil 6 of the track element E, so that, this device is permanently in its active condition regardless of the position of the contact 12. Let us furtherassume that the train'proceeds and finally gets out of the block J and enters into the next block in advance thereof, so that the ltrack relayT again picks up. Even though the contact 10 of the track relay T isA closed, the pick up circuit for picking up the homerelayH is not closed, `becausethis circuit includes the coil 6 of the track element E which has been flo l rgssiaee assumed to, ibe operi :by reason of la breakin this coil or in the flea d` Wires` leading thereto, and v'eonsequently 'the home' :relay H cannot pick up. Simii1ar1y,tihe distant relayDcanl*not pick up even'thoughthe'contact '2'11ofrthe signal Z1 ahead is closed, beca-use "its piek iup circi'iit includes fthe coil 6 which Vis 'assumed Ato be iopencircuitecl and' iindlud'es the front contact A17 of the 'home relay 'which relay -is :de-energized, rso that, 'both of these 'relays remain Adesenergized in spite of the 'fact 'that traffic conditions fahead are clear, and the signal `Z remains in the danger position by `reason vof the fact that #the coil 6 kof 'the' ftraek element' E is open `circuited,vals assumed.v

Theiarran'gem'ent shown AinlFig. 1 although it t'ake's- 'care lofthe most lco'mm'on breaks in the low resistance circuit iincludingftheyc'oil 6 'does not check this entire circuit, because the fro'ntlc'o'ntact 12 of Ethe fdistant relay D'vvhic'h 'formsva part off this low resistance circuit has *not been checked, the pick up circuit for the home relay lil including only Wire 11, coil 6 and the leads extending'therefrom, and Wires 14 and 1,5,so @that badcontact should'de vel'op at contact 121the dev-ice E vmight still be in Aits influence :communicatin g condition under .clear trai'lic conditions ahead. and While the signal Z is in 'its clear indicating position. Also, if Ian open 'civr-ciiit' should develop in the coill6 While thereareno trains around and While the signal Z is in its clear itrailic condi tion, the development of this 'open ycircuit would cause the 'track element E to Abe in vits effective stopping condition, and `out 'of correspondence with thesi-gnal Z 'which remains. in its cleartrafhc indicating position, and the occurrence vof an `open circuit at this time of course does not change the signal Z, Abecause `the stick circuit 'for 'the relays H and D are now completed through the contact 12 of the distant relay D. In other Words, the check provided in the arrangementshown in Fig. 1 is only effective to 'prevent fthesignal 'from chalnging'fr-om an adverse-'condition toa clear traffic `condition `upon open-ing of the circuit including the lovv resistance coil 6, and the ar -rangen'xent shown ydoes notplacethe signal Z in the danger position `if it Ahas once assumed its clear trailic position. A y 'A In order 't'o further check the integrity of the circuit including the coil lG, it has 'been proposed 'to Vplace-a check relay in this circuit together with a source of energy to detec't its integrity, and vsuchan arrangement is shown in the embodiment illustrated in F ig. 2. It

'should be noted that the line` Wires offthc. block I corresponding -to those-of the block` J-have'becn designated slike reference characters having a distinctive-exponent zero.

Structure (Fig. 2)

the same as that shown in Fig 1 except that reference ch'ar'a'cte'rs jas 'those in l.

Operation Z) 0bviously, the sameiprincip'le forchecking the `integrity ofthe low resistance coil f6 ofthe trackelement `E asexplained in"connec- Ation With Fig. 1 ofthe drawings is present inthe arrangement shown in Fig. 2; that is, if rxthe next signal Vin yadvance once-assumes an adverse traffic indicating -position 'and the front contact 12 of relay D is lop'en for ithis reason' andthe coil-6 of 'device IE isopen, forl some reason the relay vcannot again be picked up'because its pick-up circuitjis broken at coil Gand therefore the signal Z associatedtherevvith cannot lassume Vits clear indicating position. In-'addition Eto this check, thereis provided a check relayCK lso'tha't if an open circuit develops in the coil 6 While the signal rZ is in its clearposition the check relay CK is deenergizedbe'cause its'energizing circuit is openat thebreak in coili'G and in .turn drops its contact26 kand opens the clear circuitcl so th'at'the signal Zassumes Y its 'caution position. This check relay of course also takes care of a high resistance contact at the contact 12, Whichas heretofore 'mentione'dis apart of the circuitwhich can not be checked by the arrangement shown in Fig. V1. VIn Vpractice the check "relay CKris designed so that '.itassumes its cle-energized position d ue to a reduction 'in the vcurrent flow therein if the Vresistance of the contact 12'is high enough to cause.theltrackelement E to transmit a control 'infiuence to a pass'- ing train. vIn other Words, 'if at any time the resistance of the'buckingcircuits, including coil '6,'relay'CK an'dfthecontact 1.2 increases to a value vvhichrenders the ldevice LE `active the checkrelay kCK'yvill drop and 'the signal will goto caution. .Y .Sincethe cur- :rent .foi-energizing the checkrelayGKmust fiowlthrough the low resistance coil 6 of the tracleelement E a'Wea-lr. magnetic ieldema l 'nates from theEpOle Ypieces of this track: element. This field lalthough it is lvery kWeak is preferablyso poled that `it opposes the magnetism set upbythe primary` -coil ofthe ear apparatustofbe used'therewith, such, for

instance, as sh'oWnin the' application of F. L.

Dodgson, Ser. No. 726,781, iiledJuly 18,1924.

. 'In other Wordsf'the Weak fieldproduced by the '-rtracl; 'element E Vslightly opposes A"the transmission of acontrol influence and`there= 'by improves theopera'tion of the system, or rather, is lessiapt t0, cause a transmissionof acontrol 1nuence'under'clearttrac condif tions, that is, when vthis coil 6 is .closed in a circuit including the check relay C and the battery 25.

In the arrangements shown Vin Figs. 1 and 2 the trackvvay influence communicating device E andthe signal Z are both operated Yseparately by the relays D and H. For reasons already given the system shown in Fig. 2 is such that failure of the track element E to be in a condition corresponding to traflic conditions ahead when such traffic conditions are favorable causes the ksignal Z to assume a condition corresponding to `that of the track element E in spite of favorable traiiic conditions ahead. In addition to this possible discrepancy between the operating conditions of the track element E and the signal Z, the signal Z may be in the danger indicating position by reason of its being out of order and being constructed to function on the side of safety; and if it is desired to bring the track element E into harmony with the signal under such conditions an additional contact, operated by the vsignal Z and closed when the signal is at clear is connected in series with the contact 12 of the relay D.

Structure fig. 3)

The arrangement shown in Fig. 3 of the drawings is very similar to that shown in Fig. 1 and differs therefrom only in slight details presently pointed out, and therefore like parts have been assigned like reference characters. In the arrangement shown in Fig. 3 the front contact 19 of the distant relay D has beenomitted. Further, the coil 6' of the track element E has a tap brought out from the mid-point of its Windingivhich is connected to a Wire including the check relay, the battery 25, and a resistance 29, which resistance is at times short-circuited by the contact blade 27 of the signal Z, this circuit dividing into two branches each including one half of the low resistance coil 6. rthis arrangement is provided so that the current for energizing the check relay Ck divides itself into two components and these components flow through. the nfinding'of the coil 6 in opposite directions, so that one component neutralizes the other andy so that there is no magnetic held emitted by the track element E. Since in the arrangement shown in Fig 3 the coil 6 is divided into two lparts one of which may be shunted by the contact 12 of the relay D, an additional contact 28 has been provided onthis relay D which contact shunts in the other portion of this coil 6, 'Operation (1779.3)

The operation 'of the system shown in Figs. 2 and 3 is identical, so that the sopera; tion of the system shown in Fig. 3 need not be considered in detail. It should, however, be noted that there is no magnetic field emitted by the track element Eby reasonof thefact that the current tlowing in check relay C7: flows through the coil 6 in tWo com'- ponenteY which neutralize each other, and that if anv open circuit occurs in one part of the coil 6 or its associatedl lead Wire that the current flow through the check relay Ck is notentirely cut oft, but is merely reduced in value, because the current iioWing-in one of the. tWo circuits in multiplehas discontinued to flow. In order to assure that this check relay Ck will assume its de-energized posi,- tion in response to thesmall change in current iovv effected if one part of the coil 6 becomes open circuited, the resistance 29 has been provided in this circuit Which resistance is shunted by contact 27 When the signal Z is at caution or danger. The various constants of the circuit including the check relay Cla, battery 25 and resistance 29 are in practice so 'chosen lthat the check relay Cla cannot pick up'ivhen one ofthe portions of coil 6 is opencircuited due to circuit failures, or the like, even ihough the resistance 29 is shunted by contact 27, and so that the check relay is sure to drop ify one portion of the coil 6 is open circuited and contact 27 is open. In order to get a clearer understanding of this portion of the. arrangement shown in Fig. 3 let us assume that the. signal is at clear and one of the portions of coil 6 is open-circuited. This Will cause the check relay C70 to drop, which in turnby dropping contact 26 causes the signal Z -to assume the caution position. With the signal Z at caution the resistance 29 is shunted by Contact 27 but in spite of the increase in the current due to this reduction in the resistance of this circuit, insufficient current to pick up the check relay C76 Will flow. In other Words, the resistance 29 and contact 27 have been provided so that if the currentlowing in the check relay has been reduced to a value so that this relay can not pick up, this relay will assume its de-energized position, although it already Was in its picked up positionv when the current was so reduced, this additional resistance being inserted inv series therewith when the check relay shouldassum'e its de-energized position and vif it is still in its energized position this insertion of resistance causes it to assume its Cle-energized position, whereby even though this additional resistance is again shunted out of the circuit the relay is unable to again pick u p.

- Structure (Fig. .4)

VIn Fig. has been illustrated a ramp system to which the present invention is ap- Y plied, showinga ramp R which under clear traiiic conditions has a potential with respect to he ground applied thereto, and more particularly with respect to the track rails,

`as Yis common in train control systemsjof susanna:1

ront contact 3U of theV distantrelay D" and it suitable source; of energ this source:y of

electrical` energy which may be' either alter- Hating or' direct incha-racter Abeing-iol' convenience illustratedA ascoinprising aI battery iid.` In ordertoassure that the signal indif cationy oit-fthe Wayside signal Z'correspond'slito thatoffthe'cond-ition of the ramp When this ramp, by reason of'an` open circuit orthelilre, is not in its clear traiic condition when itshould' be, a1 check relay C76 isA connected between a certain point on this ramp-j and the track rails-,Iso that this checkrelay Ck assumes the energized condition `Whenever the ramp R` isenergized. This check relay Ck, ofcourse, has any internal resistance of a value that does not interfere with the proper operation of the car relay (not shown), and furl ther has characteristicssuch that it is not effectively shunted by such car relay or effected in any other way'by'the passage of a train equipped With the usual contact shoe and car relay. This check relay CL as well2 as the various circuits controlled thereby are the same as corresponding devices shown in Fig. 2 of the drawings and alradyV described, except that the ener'- gizingcircuits iortherelays H and D go direetly tothecominon return Wire C instead of'including aligr'ont conta-ct 12 of the relay D. Operation 4) The signal Z in Fig. 4- ofthe drawings is governed bythe relays H, D and in exactlyA the saine Way as isthe signal in Fig. 2, thaty is=,tlie` signal? cannot assume or remain in the clear position it the check relay @la is in the dey-energized position, this because the clearv or .()OP'Wi-re` clinclud'esboth thefcontact 30 of thefdistant relay D and thel front contact 26A of" the check relay' Ck. The lfunctioning ot the check relay Cla is ot course understood,

this relay being one of the potential type the sameas the usual cari relay employed in ramp systems,` and' this check relay is momentarily connected in multiple With such car relay upon the passage ofa train. VWhen there is no tra-in passing by and traffic conditions alieadlareclear, this check relay is connected directlyI across-the battery' 31 through the fronti contact of the distant relayV D, sov

" jacent to an elementhaving'its coil: open circuited accidentally must assume theV danger position; whereas in Fig. 4 the signal is only prevented from assuming the clear position when the energizing circuit for the ramp R isaccident-'allybreken, that is,V may either assuine the caution Ior danger position :dependingf onl trailic conditions ahead. Either of theseexpedients are considered safe, but inY the event the signal iscaused to assume the danger position as-it is in Figs. 1,2 and 3, the next signal in therear should be,v directly governedlby theV signal in question and not only by the several relays which indicatefactual traffic conditions ahead',l in order that an approaching train-,Will be properly informed by a caution signal belore'it reaches a signal at' stop reason of failurel of a trackway device.

Having thus shown anddescribed several specific embodiments ofthe invention, it is desired tobe understoodthat the specific arrangements shown have been selected' orthe` purpose-oi illustrating its scope or'the. exact construction preferably'employed in practice,

andx that" various changes and modifications may-` be made to adaptthe invention to the' particular type of influence communicating means employed in connection with the train control system to which the present invention is to be applied, for instance,if the present inventionis tolle applied to a system'v'in which thetracl-way device includes a 'permanent magnet and ardeiecting or bucking coil', which coilis energized under clear tra-Bic confv ditions, the directr` current Vtor' energizing this bucking coil may be' employed to'control the check `relay,Without depart-ing `from y the scope of the invention'vorth'eidea of means underlying'thesame; 4. p

Vhat' it isdesired to be secured by Letters Patentisz- 1. Trackway systems of thet intermittent' inductive type, comprising the combination' of a Wayside signalL control-'led' in accordance with traiiic conditions ahead of such .signal for the particular direction of traliic controlled by said signal, and inductive trackway device in clu'dinga coil closedl in 'a deenergized circuit of' low-'resistance when said' trackway device is in its clear inactive condition, a relay hav'- ing its Winding connected in series Withl said apparatus for train controli i coil and? adapted to change'from its de-en'- ergized Ito its energized condition only if saidE coil is intact, said relay placingA said Wayside' signal in anA adverse trailic indicating conditiony when' said' relay' assumes its defenergizedi condition, whereby said signal indicates dangerif said coil isaccidentally open-V circuited. l Y e v 2; Trackvvay apparatus: for train control systems of the intermittent inductive type,

comprising the combination of a Wayside f signalv controlled in accordance with traflicr conditions aheadot such signal for therpar# ticular direction o'f't'raliic controlled by said signal, an inductive tracl'rway device includ-y ing'a coilwhi'ch isconnected' ina closed deenergizedl circuit of lovv' resistance undery favorableA traffic "condition ahead, a relay hav- Lio ing its winding at times `connected in series with said coil, and means for causing said way side signal toindicate adverse traffic conditions regardless of tratiic conditions ahead when said relay is de-energized, whereby said signal will be in correspondence with said device when said coil is accidentally open-circuited. l

3. Trackway apparatus for automatic train control and signalling systems comprising, a wayside signal, traiiic responsive means including a relay for controlling said signal, an inductive traffic controlling device for transmitting control influences to a moving vehicle under adverse traiiic conditions ahead including a coil rwhich if closed circuited places said device in its inactive condition, said coil being contained in the energizing circuit of said relay and said relay having a contact in multiple with said coil closed when said relay is energized, whereby said relay can only assume its energized condition in response to a favorable change in traffic conditions ahead if the circuit of said coil is intact.

4. Trackway apparatus for automatic' train control and signalling systems comprising, a wayside signal, trahie responsive means including a relay for controlling said signal, and inductive tratiic controlling device for transmitting control iniluences to a moving vehicle under adverse traiiic conditions ahead including a coil 4which if closed circuited places said device in its inactive condition the energizing circuit of said relay including a front contact thei'eof so that its energizing circuit is a-stick circuit, said coil being bridged across 'said front contact so that this coil provides a `pick up circuit for said` relay, whereby said relay can be picked up in response to a favorable change in trafc conditions only when the winding of said coil is intact. f t

5. Trackway apparatus for automatic i train control and signalling systems comprising, an inductive' influence communicating track element which is inactive when a coil associated therewith is contained in a closed circuit, said track element being governed in accordance with tratiic conditions ahead, a wayside signal located adjacent said track element and controlledin accordance with traffic conditions ahead, and means for causing said signal to assume a condition indicating adverse traiiic conditions ahead regard-- less of tratlic conditions ahead when said coil is onen-circuited, whereby the indication of said signal will correspond to the con dition of said track element by reason of failure of the coil of said track element.

6. Trackway apparatus for automatic train control and signalling systems compris'- ing, an inductive influence communicating track element which is inactive when a coil associated therewith is contained in a closed circuit, said track element being goverened in accordance with traffic conditions-ahead, a wayside signal located adjacent said track element controlled in accordance with traffic conditions ahead, and means forpreventing said signal fromV again assuming a favorable tra-flic indicating conditions after once having assumed an adverse tratlic indicatingcondition even though tratlic conditions ahead are favorable if said coil accidentally becomes open-circuited. f

' 7. Trackway apparatus for automatic train control and signa-ling systems, the combination of a wayside signal, a trackway device for inductively transmitting control influences to a moving train under adverse traffic conditions ahead constructed so as to have an inherent tendency to assume such active condition and having an electrical circuit associated therewith effective under clear traffic conditions to remove such tendency, and means for causing said signal to assume a favorable traiiic indicating condition when said circuitis closed and for causing it to assume unfavorable traiiic indicating condition when said circuit is open. S. Trackway apparatus for automatic train control and w yside signaling systems comprising, a wayside signal, trackway means for transmitting control influences inductively to an approaching train, said means including a circuit and manifesting favorable tratlic conditions if said circuit is closed and manifesting unfavorable traiic conditionsif said circuit is open, and means for `causing said wayside signal to indicate favorable tratlic conditions when said circuit is closed and to indicate unfavorable traine conditions when said circuit is open.

9. Trackway apparatus for automatic train control and` signalling systems comprising, an inductive trackway device having a coil thereon-.and inactive to transmit control innal, means for detecting the integrity of the circuit containing said coil including a relay4 and a source of energy, means for causing said signal to assume a proceed position when said vrelay is energized, and means including another circuit for neutralizingthe effect of the current-dueto said source of energy upon said device. Y l

l0. Trackway apparatus for automatic train control and wayside signal systems comprising. a wayside s ignal, a trackway device for transmitting control influences to suitable vehicle carried means and having a circuit portion which must be intact in oider to permitV said trackway device to manifest favorable traine conditions, a stick rela-y for governing said trackway device and said wayside signal an dhaving a front contact closed when said relay is energized, a stick circuit including the winding and the front contact of said on. L; c'

CII

relay, a pick-up circuit for said relay including the winding of said relay and said circuit portion, said wayside signal and said trackway device indicating favorable traffic conditions when said relay is energized and indicating unfavorable traffic conditions when said relay is cle-energized, whereby the failure of integrity of said circuit portion causes said signal te indicate adverse traffic conditions.

1l. Trackway apparatus for automatic train control and wayside signalling systems comprising, a wayside signal, trackway means for transmitting control influences inductively to an approaching train, said means includ'- ing a coil and manifesting favorable trafiic conditions if said coil is included in a closed circuit of low resistance and manifesting unfavo able traffic conditions if the circuit of said coil is open, and means for permitting said wayside signal to indicate favorable traffic conditions only when the circuit for said coil is closed and for causing said signal to indicate unfavorable traffic conditions when said circuit is open.

12. T rackway r apparatus for automatic train control and signalling systems, the combination of a waysi-de signal, atrackway device for inductively transmitting control influences to a moving'train under adverse traffic conditions ahead constructed so as to have an inherent tendency to assume such active condition and having a coil associated there with which if included in a circuit of low resistance will remove such tendency and which under clear traffic conditions is included in a circuit of low resistance, and means for permitting said signa-l to assume a favorable trafiic indicating condition when said coil y is electrically intact and for causing said signal to assume an unfavorablev traffic indicating condition when the integrity of the circuit of said coil is broken.

13. Trackway apparatus for automatic train control and signalling systems comprising, an inductive trackway device having a coil thereon and inactive to transmit control influences when said coil is closed in a de-energized circuit of low resistance, a wayside signal, means for detecting the integrity of the circuit containing said coil including a relay and a source of energy, means for causing said signal to assume a proceed condition when said relay is energized, means including another circuit for neutralizing the effect of the current due to said source of energy upon said device, and means for inserting additional resistance in series with said relay under clear traffic conditions so that if either said first mentioned. circuit or said another circuit is broken while clear traffic conditions exist insuiiicient current to maintain said relay energized will flow. I

14. Railway traffic controlling apparatus comprising a train controlling device located in thetrackway and including awinding, a relay'located.y in the trackway, a path, of'liow resistance for said winding including acontact. on*` said. relay,` and; means: for at times supplying energy to1- saidrelay through said winding;

l5. Railway traffic controlling apparatus comprising ai section ofrailwaytrack', ai train. controlling inductor lo cateda in. the '4 trackway and comprising. a winding, a. relay, ai cincuit.

for saidf relay' controlled bytraiiicconditions by. said: track.,relay and including substanztially? all of said shunting; circuit eXceptsaid contact.. i.

1-7. Railwaytraihcvv controlling apparatus comprising-a; trac'ltway ydevicef including a winding,xa first circuit for at time close circuiting said winding, a second. circuit includ'- ing'substantially all of `saidT first' circuit, aind a trackwaiy signal controlled by said second circuit.

18. Incombination, a railway track, a track relay, a line relay, a trackway inductor including a windinga circuit for said line relay including said winding and a contact on said track relay, a low resistance circuit for said winding including a contact controlled -by said line relay, and a trackway signal controlled by said line relay.

19. In combination, a section of railway track, a signal associated with the section, a line relay controlled in vaccordance with traffic conditions, an isolated inductor circuit controlled by theline relayand including a checking rela for controlling the signal.

20. In com ination, a section yof railway track, a signal associated with the section, a

line relay controlled by traffic conditions in adyance, a trackway inductor having a circult controlled by the line relay, and a checking relay in series with the inductor circuitV for controlling the signal.

21. In combination, a section of railway track, a trackway inductor for said section, a signal associated with said section ,and having a proceed and a caution circuit,` a winding on the inductor, a circuit for said inductor winding controlled by trafiic conditions in advance and including a relay in series with theV winding, and means for closing the proceed circuit for said signal when and only when said relay is energized.

Q2. In a railway traffic controlling apparatus, the combination with a section of track and a trackway signal, of a track relay connected to the section, a line relay having a plurality of front contacts andl controlled jointly by the track relayof the adjacent section and the section next in advance, a track- Way inductor, a Winding on the inductor, a circuit for said inductor Winding including a checking relay anda front contact of said line relay, said checking relay having a front contact, and a proceed circuit for the signal including a front contact of the checking relay and a front contact of the line relay.

23. In combination, a section of railway track, a train controlling inductor located in the trackway and provided with a Winding, an isolated circuit for said inductor Winding controlled by traiiic conditions in advance, a signal associated with said track section, and means for causing said signal to indicate proceed when and only When said isolated a@ circuit is closed.

24. In combination, a railway track, a track relay, a line relay, a trackway inductor including a Winding, a circuit for said line relay including said Winding and controlled 25 by said track relay, a low resistance circuit for said Winding including a 'Contact on said line relay, and a'trackvvay signal controlled by said line relay. 7,

In testimony whereof I afix my signature.

:lo FRANK L. DODGSON. 

